Diseases

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DEFINITION The liver is an organ about the size of a football that sits just under your rib cage on the right side of your abdomen. The liver is essential for digesting food and ridding your body of toxic substances.…

DEFINITION Dressler’s syndrome is a type of pericarditis, inflammation of the sac surrounding the heart (pericardium). Inflammation associated with Dressler’s syndrome is believed to be an immune system response following damage to heart tissue or the pericardium, such as a…

DEFINITION Lichen sclerosus (LIE-kun skluh-ROW-sus) is an uncommon condition that creates patchy, white skin that’s thinner than normal. Lichen sclerosus may affect skin on any part of your body, but most often involves skin of the vulva, foreskin of the…

DEFINITION A drug allergy is the abnormal reaction of your immune system to a medication. Any medication — over-the-counter, prescription or herbal — is capable of inducing a drug allergy. However, a drug allergy is more likely with certain medications.…

DEFINITION Liposarcoma is a rare type of cancer that begins in the fat cells. Liposarcoma is considered a type of soft tissue sarcoma. Liposarcomas can occur in fat cells in any part of the body, but most occur in the…

DEFINITION A lipoma is a slow-growing, fatty lump that’s most often situated between your skin and the underlying muscle layer. A lipoma, which feels doughy and usually isn’t tender, moves readily with slight finger pressure. Lipomas are usually detected in…

DEFINITION Lichen planus (LIE-kun PLAY-nus) is an inflammatory condition that can affect your skin and mucous membranes. On the skin, lichen planus usually appears as purplish, often itchy, flat-topped bumps. In your mouth, vagina and other areas covered by a…

DEFINITION Limited scleroderma, or CREST syndrome, is one subtype of scleroderma — a condition that literally means “hardened skin.” The skin changes associated with limited scleroderma typically occur only in the lower arms and legs and sometimes the face and…

DEFINITION Lip cancer occurs on the skin of the lips. Lip cancer can occur anywhere along the upper or lower lip, but is most common on the lower lip. Lip cancer is considered a type of mouth (oral) cancer. Treatment…

DEFINITION Lice are tiny, wingless, parasitic insects that feed on your blood. Lice are easily spread — especially by schoolchildren — through close personal contact and by sharing belongings. Several types of lice exist: 
 
 Head lice. These lice…

DEFINITION Lewy body dementia, the second most common type of progressive dementia after Alzheimer’s disease, causes a progressive decline in mental abilities. It may also cause visual hallucinations, which generally take the form of objects, people or animals that aren’t…